Mac the Scope measurement of Waavebox multi-harmonic sine
waveform output. Fundamental was set to 1 kHz. Harmonics # 2.11,
3.4, 4.3 and 4.7 were selected and mixed; relative amplitudes
were set at 0, -20, 0, 0 and -10 dB, respectively (overall amplitude
is set with the Waavebox LEVEL control).